Karam, who started fifth in the No. 8 Schmidt Peterson with Curb-Agajanian car, held off the repeated charge of Gabby Chaves to win by .2660 of a second in a caution-free race on the .875-mile oval. Jack Hawksworth completed the podium sweep for the team co-owned by Sam Schmidt and Ric Peterson. Firestone Freedom 100 winner Peter Dempsey placed fourth.

It was the second consecutive victory for Karam, who supplanted Carlos Munoz atop the standings by nine points. Munoz, the pole sitter for the fourth time this season, finished eighth (three laps down) in the No. 26 Dialy-Ser car for Andretti Autosport.

It also was the fourth consecutive year that Karam has won at Iowa Speedway in the Mazda Road to Indy -- USF2000 in 2010 and Pro Mazda the succeeding years.

“I saw the opportunity, took it and that was it," said Karam, who overtook Hawksworth for the lead on Lap 49 and led the rest of the way. "We had a good race. I will tell you what, that was one of the hardest victories I’ve had to work for. That definitely goes down as the best drive I’ve ever had.”

Chaves moved to second on Lap 90 as the leaders caught lapped traffic. He close to .2860 of a second with 10 laps remaining but couldn't run down Karam off the corners.

"I felt that we had the strongest car at the end of the race," said Chaves, who earned his fourth podium finish. "It’s a bit hard running in dirty air. I had a good run on Sage and he defended. It’s just hard keeping the car down on the racing line when you’re so close to the car in front as well as trying to keep another car behind you. You’re working twice as hard.

"Another good points finish, another podium. Disappointed we didn’t get the win because we definitely had the car. We’ll just put our heads down and keep working forward."

Hawksworth recorded his third podium of the season -- the first since early April at Barber Motorsports Park.

Munoz said he had an issue with the front tires from the first lap.

"We were good all weekend and then something was wrong with the race," he said. I"t's a shame for the championship ... now we have to think about Pocono."

Next up is the 2.5-mile Pocono Raceway, where the series -- then known as the CART American Racing Series -- last raced in 1989. Tommy Byrne won the race. Karam lives in nearby Bushkill Township, Pa.